(NaturalNews) The FDA has admitted that meat and milk from the offspring of cloned mammals such as cows, pigs, goats and sheep could very well have already entered the food supply in the United States.

In January, the FDA declared that foods derived from cloned animals and their offspring were safe for human consumption. The U.S. Department of Agriculture, however, asked food companies to voluntarily maintain a ban on products from clones.

The voluntary ban did not extend to the offspring of cloned animals.

Clones are organisms artificially developed directly from the DNA of a single organism, rather than the mixing that is difficult in sexual reproduction. They are made by implanting the nucleus of an adult cell into an egg cell, which is then incubated by a surrogate mother.

According to critics of the technology, very little research has been conducted on the safety of consuming meat or dairy products from clones or their offspring, thus making it premature to bring such products to market.

"It worries me that this technology is out of control in so many ways," said Charles Margulis of the Center for Environmental Health. He said that the FDA's announcement that clones' offspring might already been food supply "is just another element of that."

A number of major U.S. food producers have announced that they will not use any ingredients derived from cloned animals, due in part to safety concerns. Companies enforcing a ban on clone products include Smithfield Foods, General Mills, Campbell Soup, Nestle, California Pizza Kitchen, Supervalu, Kraft Foods and Tyson Foods, the largest meat company in the United States.

Kraft said that consumer demand influenced its decision.

"Research in the United States indicates that consumers are currently not receptive to ingredients from cloned animals," said Director of Corporate Affairs Susan Davison.